Commit 1a6d80ff authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux 

Pull arm64 fix from Will Deacon:
 "We received a report this week that the generic version of
  pfn_valid(), which we switched to this merge window in 16c9afc7
  ("arm64/mm: drop HAVE_ARCH_PFN_VALID"), interacts badly with
  dma_map_resource() due to the following check:

        /* Don't allow RAM to be mapped */
        if (WARN_ON_ONCE(pfn_valid(PHYS_PFN(phys_addr))))
                return DMA_MAPPING_ERROR;

  Since the ongoing saga to determine the semantics of pfn_valid() is
  unlikely to be resolved this week (does it indicate valid memory, or
  just the presence of a struct page, or whether that struct page has
  been initialised?), just revert back to our old version of pfn_valid()
  for 5.14.

  Summary:

   - Fix dma_map_resource() by reverting back to old pfn_valid() code"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  Partially revert "arm64/mm: drop HAVE_ARCH_PFN_VALID"
parents 97d8cc20 3eb9cdff

arch/arm64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -156,6 +156,7 @@ config ARM64 
	select HAVE_ARCH_KGDB

	select HAVE_ARCH_MMAP_RND_BITS

	select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT

	select HAVE_ARCH_PFN_VALID

	select HAVE_ARCH_PREL32_RELOCATIONS

	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET

	select HAVE_ARCH_SECCOMP_FILTER

arch/arm64/include/asm/page.h

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ void tag_clear_highpage(struct page *to); 


typedef struct page *pgtable_t;



int pfn_valid(unsigned long pfn);

int pfn_is_map_memory(unsigned long pfn);



#include <asm/memory.h>

arch/arm64/mm/init.c

+37 −0
Original line number Diff line number Diff line
@@ -219,6 +219,43 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max) 
	free_area_init(max_zone_pfns);

}



int pfn_valid(unsigned long pfn)

{

	phys_addr_t addr = PFN_PHYS(pfn);

	struct mem_section *ms;



	/*

	 * Ensure the upper PAGE_SHIFT bits are clear in the

	 * pfn. Else it might lead to false positives when

	 * some of the upper bits are set, but the lower bits

	 * match a valid pfn.

	 */

	if (PHYS_PFN(addr) != pfn)

		return 0;



	if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)

		return 0;



	ms = __pfn_to_section(pfn);

	if (!valid_section(ms))

		return 0;



	/*

	 * ZONE_DEVICE memory does not have the memblock entries.

	 * memblock_is_map_memory() check for ZONE_DEVICE based

	 * addresses will always fail. Even the normal hotplugged

	 * memory will never have MEMBLOCK_NOMAP flag set in their

	 * memblock entries. Skip memblock search for all non early

	 * memory sections covering all of hotplug memory including

	 * both normal and ZONE_DEVICE based.

	 */

	if (!early_section(ms))

		return pfn_section_valid(ms, pfn);



	return memblock_is_memory(addr);

}

EXPORT_SYMBOL(pfn_valid);



int pfn_is_map_memory(unsigned long pfn)

{

	phys_addr_t addr = PFN_PHYS(pfn);